Shirred cellulose casing used in the manufacture of sausage and/or hot dogs requires very specific packaging. The cellulose casing consists of regenerated cellulose, made in a tube, and described by numerous patents including U.S. Pat. Nos. 1,070,766; 1,158,400; 1,163,740; 1,601,686; 1,612,508; 1,645,050; 1,654,254; 2,999,756; 2,999,757; 3,835,113; 4,590,107; 4,778,639; and 5,358,765.
The tubular casing is typically moisturized and shirred on conventional shirring machines into a compressed tube, which compressed tube is commonly referred to as a shirred stick. Length reductions of 100 to 1 are common, that is, 100 feet of tubular casing is compressed and compacted into a shirred stick having a final length of one (1) foot, which greatly eases handling and dispensing on commercial sausage machines. A typical shirred stick has two hundred and twenty five (225) feet of casing, capable of producing over six hundred (600) hot dogs when filled with meat paste. Typical shirring patents include: U.S. Pat. Nos. 2,010,626; 2,498,948; 2,583,654; 2,722,714; 2,983,949; 3,222,192; 3,461,484; 3,452,982; 4,550,472; and 3,397,069. Moisturizing the casing during shirring is shown in many patents, such as U.S. Pat. Nos. 3,097,393; 3,110,058; 3,222,192; 3,451,827; 3,462,794; 3,898,348; 4,062,980; 4,062,981; 4,596,727; and 5,230,933.
Shirred sticks are somewhat fragile and it is critical that the shirred sticks are packaged adequately. Any loss of moisture, coherency or other critical variable can ruin the shirred stick. Thus, it is important that the packaging of the shirred sticks perform several functions. For example, the packaging should rigidly support the shirred sticks in order to prevent lateral abrasion, excess motion, and dimensional changes such as curving, bowing, and loss of stick coherency (in which the pleats un-nest and come apart), despite the presence of length or diameter variations. The packaging should be easy to open, provide for easy dispensing of the shirred sticks, and enhance moisture retention in the shirred sticks. It is also desirable that the packaging be easy to dispose of or recycle, and minimize the overall package volume in order to ease transportation and storage. Finally, the packaging should protect the shirred sticks against accidental wetting while the sticks are awaiting use in the stuffing room.
According to conventional practice, the shirred sticks are commonly bundled together in quantities of fifty (50) sticks. Each bundle of fifty sticks is called a caddy. Most meat packers prefer this conventional number of fifty sticks per caddy for ease of ordering and record keeping. Multiple caddies may be packed in a common carton or box, with typical cartons containing 4, 6 or 8 caddies, depending upon weight and convention. Each carton is opened outside the meat kitchen, and the caddies are individually carried into the kitchen.
In order to package shirred casing, several alternatives are possible. One approach has been to package the shirred casing in a rigid cardboard boxes, while another approach has been to use plastic packaging. Examples of rigid cardboard caddies can be found in many U.S. patents, such as U.S. Pat. Nos. 2,028,691; 2,181,329; 2,794,544; 3,028,952; 3,148,992; 3,250,629; 3,271,168; 3,321,072, 3,342,322; 3,471,305; 3,528,825; 3,616,989; and 3,627,116.
Although cardboard boxes are accepted in the industry as providing the best overall protection of shinned casings, due to hygienic reasons an increasing number of meat processors do not wish to have cardboard present in the sausage kitchen. Such processors thus require the use of all plastic caddies.
The general concept of plastic packaging can be found in many prior art U.S. patents. For example, U.S. Pat. No. 1,251,598 shows a concept to package tubular products in flexible pouches. U.S. Pat. No. 2,682,475 shows an early form of plastic packaging. U.S. Pat. No. 2,814,382 shows a product vacuum packed within a tightly-wrapped cellophane pouch in order to create an air tight container. U.S. Pat. No. 2,967,383 illustrates using thermally sensitive film that heat shrinks around a product and which also utilizes an internal vacuum to create a tightly wrapped article. U.S. Pat. No. 3,206,020 also illustrates a shrink wrapped film. Finally, U.S. Pat. No. 3,164,934 shows a device that employs a snorkels to vacuum seal a product in a heat sealed container.
The general concept of bundling a number of similar articles together is shown in U.S. Pat. Nos. 3,218,764, 3,875,723 and 3,283,893. Use of moisture barrier films and liners is shown in U.S. Pat. No. 3,233,815, while shrink wrapping of shirred sticks using plastic packaging with cardboard end supports is shown in U.S. Pat. No. 3,764,351.
U.S. Pat. No. 3,971,187 to McNeill shows vacuum packaged caddies of 50 shirred sticks. Configurations include 5.times.10 stacking, and 6-5-6 stacking. McNeill describes clearly the benefits of vacuum packaging, such as avoiding the tendency of going to a "round" shape created by shrink packaging methods. McNeill uses a film impervious to air passage having a vapor transmission rate less than 1 cc/100 in 2/24 hour/atm. McNeill also envelopes individual layers around separate rows. Evacuation is made to preferentially 0.6 to 0.75 atm, or between 3.7 and 5.9 in. Hg vacuum. McNeill describes vacuums exceeding 0.4 atm or exceeding 8.8 in. Hg as excessive and which will flatten the sticks.
U.S. Pat. No. 4,295,563 shows using impermeable pouches over wrapping shirred sticks where the interior of the pouch is gas flushed, while U.S. Pat. Nos. 4,671,414; 4,730,437; 4,796,754; and 5,467,576 show automatic packaging.
Conventional plastic packages for casings are shown in several patents. U.S. Pat. Nos. 5,137,153 and 5,228,572 uses a hexagonal package, with rows containing the following shirred sticks: 4-5-6-7-6-7-6-5-4, to reach 50. The package is not vacuumized. It also is unstable when laid on a flat table and can tip easily. Similarly, U.S. Pat. Nos. 5,356,007; 5,381,643 and 5,391,108 show using a stretch film to make a wrapping, with the stretch film being sealed with a low adhesive tape. This article is not vacuumized and it has been shown that in hot weather, the film can relax sightly, allowing excessive movement of the shirred sticks which bows and curves the sticks. Moreover, the caddies must be shipped in a double wall carton to protect them, which results in excessive use of cardboard.
U.S. Pat. No. 5,382,190 shows a caddy with layers of: 7-8-9-8-7-6-5 to add up to 50 sticks, while U.S. Pat. No. 5,727,364 and European Patent No. 0,672,593 A2 to Artieda show a packaging means with 5.times.10 stacking using an adhesive tape as a handle and wrapping the sticks in a non-shrink, non-stretch film. Although the Artieda package has a nice appearance, it has been found that any rough handling of the package immediately destroys the integrity of the 5.times.10 stack and the package slumps into a round or oval shape. Also, using the package is tricky in that if the package opens prematurely, sticks will slip onto the floor.
Each of the above-mentioned approaches suffers from one or more drawbacks, and accordingly there remains a need for an improved means of packaging.